Description
Accentors are a small, somewhat obscure family of small, brown, superficially sparrow-like birds that feed on the ground. Not many people on the street have even heard of them, and even fewer would know that they are any different from lots of other small brown birds.
But accentors are different, for two reasons, one anatomical and one behavioural. The anatomical feature that stirs the juices of specialists is the unique bill. It has a very sharp point, allowing accentors to eat rather small food items, but is wide at the base, and the upper mandible is so swollen in shape that it is actually round in cross section – very strange. It is often used for flicking leaves dismissively aside as the birds feed.
Accentors may be modestly coloured and retiring in habits, but their sex life is extraordinary, if not unique. Put simply, it involves many different options for pair-bonding, not just monogamy but also various forms of polygamy, including polygyny (one male, more than one female), polyandry (one female, more than one male) and both of these at the same time, so called polygynandry (a male paired to two or more females, the latter in turn paired to two or more males, including the first). Not only do Dunnocks exercise all these options, but their copulatory behaviour is also unique – see the individual accounts below.
The odd name “accentor” simply means “singer”, from the Latin cantor.
| Habitat | Dunnock in woodland and scrub, usually in lowlands. Alpine Accentor in mountains. |
|---|---|
| Food | Insects taken on the ground; some seeds in autumn and winter. |
| Movements | Dunnock is resident in much of west and central Europe, migratory in the east and north, but only going as far as southern Europe. Alpine Accentor mainly an altitudinal migrant, but some move much further. |
| Voice | Main call of Dunnock is plaintive “seep”, that of Alpine Accentor a rippling “chirrup” very like Skylark. Song of Dunnock a cyclical phrase resembling the sound of the wheels of a squeaky trolley; Alpine Accentor’s song is similar, but slower and more musical. |
| Pairing style | May be monogamous and practise all the versions of polygamy: polygyny, polyandry and polygynandry. See text. |
| Nesting | Dunnock solitary and territorial, although several males and females may share territories (see text). Alpine Accentor groups live together in a shared home range. |
| Nest | Cup of twigs, stems and roots, lined with fine materials such as hair and moss. Dunnock in bush or hedge, Alpine Accentor in rock crevice. |
| Productivity | 1-2 broods a year. |
| Eggs | 4-6 eggs in Dunnock; clutch is larger in polyandrous trios if both males, rather than just the alpha-male, have copulated with the female. 3-4 in Alpine Accentor. |
| Incubation | 12-15 days, by female only. |
| Parenting style | Both sexes feed and tend the young, but the males do so on condition that they have copulated with the female concerned first. |
| Young | Nest-bound, altricial and with some down. |
| Food to young | Small insects, a few seeds. Alpine Accentor grinds seeds up in its crop before feeding them to young. |
| Leaving nest | Young Dunnocks fledge at 11-12 days, but sometimes leave nest a day before they can fly. They are fed by the adults for 14-17 days thereafter. Young Alpine Accentors leave at about 16 days, also largely flightless. |